Sodwana Bay Research Articles

Send nudis: An assessment of nudibranch diversity in Sodwana Bay, South Africa.

Climate change is posing unprecedented pressure onto marine ecosystems worldwide. This makes it imperative to monitor the effects that are being experienced in these environments. Nudibranchs are benthic marine organisms that possess characteristics that have the potential to act as indicators of change within ecosystems such as coral reefs. Therefore, these species have the ability to provide valuable information on fine-scale changes in environmental conditions. It is thus essential for studies, such as this, to establish baseline analyses from which changes within nudibranch populations can be examined in order to investigate their ability to act as bioindicators. Recommendations can also be made for future sampling procedures through investigating environmental and experimental parameters that influence nudibranch communities. Nudibranch populations were sampled on Two-Mile Reef in Sodwana Bay, South Africa, through SCUBA where individuals were photographed and later identified. Data were collected within a sample-based dataset, as well as by citizen scientists within an incidence-based dataset. Across both datasets, a total of 85 species were identified. Nudibranch populations showed high levels of diversity within an uneven, unstable community. Citizen scientist data provided imperative information to the baseline assessment and, therefore, the inclusion of these data increased the robustness of this study. Environmental and experimental variables investigated did not influence the outcomes of this study and should therefore not be heavily focused on in designing future experiments. Future monitoring studies should continue to record oceanic pH in order to detect any possible changes due to ocean acidification. It is recommended that sampling events should be increased in order to capture all species present in these localities. These events should also encompass an extended temporal scale in order to cover a larger temperature range. Research on bioindicators is essential within today's rapidly changing climate, mainly due to human activities, particularly within an extremely vulnerable habitats such as coral reefs.

A new species of Siphoderina Manter, 1934 (Digenea: Cryptogonimidae) infecting the Dory Snapper Lutjanus fulviflamma (Teleostei: Lutjanidae) from the east coast of South Africa

Parasitological assessment of marine fishes at Sodwana Bay in the iSimangaliso Marine Protected Area on the east coast of South Africa revealed a new species of cryptogonimid trematode infecting the pyloric caeca of the Dory Snapper, Lutjanus fulviflamma (Forsskål) (Lutjanidae). The new species is morphologically consistent with the concept of the large genus Siphoderina Manter, 1934; its phylogenetic position within this genus was validated through molecular sequencing of the ITS2 and partial 28S ribosomal DNA sub-regions. We name this species Siphoderina nanan. sp. and comment on the current state of understanding for this genus of cryptogonimids.

Southward range extension and transboundary movements of reef manta rays Mobula alfredi along the east African coastline.

Opportunistic in-water and aerial surveys in South Africa and the analysis of contributed citizen science data have extended the known range of reef manta rays Mobula alfredi along the eastern coast of Africa by 140 km (to Mdumbi Beach) and verified the first transboundary movements for the species. Additionally, six new long-range dispersal records have provided evidence of connectivity with the M. alfredi population off the Inhambane coastline of Mozambique. Five of these records captured one-way movements, the longest of which was an individual that travelled 505 km from Praia do Tofo to Sodwana Bay with 301 days between sightings. A single individual made a return trip between Závora, Mozambique and Sodwana Bay, South Africa (a total distance of ~870 km). These findings support the Convention on Migratory Species listing for the species, suggesting regional transboundary management units are warranted for this wide-ranging elasmobranch.

On the reef scale hydrodynamics at Sodwana Bay, South Africa

On the reef scale hydrodynamics at Sodwana Bay, South Africa

Observations on feeding behaviour of adults of the Common Buff butterfly, Baliochila aslanga (Lycaenidae: Poritiinae) at extra-floral nectaries on Adenopodia spicata (Mimosaceae)

Novel feeding behaviour by adult Common Buff butterflies, Baliochila aslanga (Lycaenidae: Poritiinae), is reported on. Nectar assimilation from extra-floral nectaries is known for a number of members of the Poritiinae, and some species also obtain their energy requirements from hemipteran honeydew excrement. We document the first record for the genus Baliochila of an adult butterfly feeding at extra-floral nectaries. Baliochila aslanga was observed imbibing nectar from petiolar glands of Adenopodia spicata (Mimosaceae) in Sodwana Bay National Park in KwaZulu-Natal, South Africa. The searching behaviour to locate the glands and subsequent feeding behaviour, as well as the petiolar glandular morphology, is described and supported by high quality photographs.

Two new Erichsonius species of iSimangaliso Wetland Park in KwaZulu-Natal Province, South Africa (Coleoptera: Staphylinidae, Staphylininae).

Two new Erichsonius (Sectophilonthus) species of South Africa (type locality: KwaZulu-Natal Province: Sodwana Bay) are described, illustrated, and distinguished from similar species: E. (S.) sodwanaensis sp. nov. and E. (S.) muellerae sp. nov.

Antimicrobial Susceptibility Profiles among Pseudomonas aeruginosa Isolated from Professional SCUBA Divers with Otitis Externa, Swimming Pools and the Ocean at a Diving Operation in South Africa.

SCUBA divers are predisposed to otitis externa caused by Pseudomonas aeruginosa, which is becoming increasingly multi-drug resistant (MDR). The present work assessed the antibiotic resistance profiles of P. aeruginosa obtained from SCUBA divers and their environment in Sodwana Bay, South Africa. Bacterial isolates from a total of 137 random water and ear swab samples were identified using biochemical and molecular methods. P. aeruginosa strains were further evaluated for antibiotic susceptibility using the Kirby–Bauer assay. Double disk synergy test (DDST) to confirm metallo-β-lactamase (MBL) production and PCR amplification of specific antibiotic resistance genes was performed. All (100%) 22 P. aeruginosa isolates recovered were resistant to 6 of the β-lactams tested including imipenem but exhibited susceptibility to trimethoprim–sulfamethoxazole. MBL production was observed in 77% of isolates while the most prevalent extended-spectrum β-lactamase (ESBL) genes present included blaAmpC (86.9%) followed by blaTEM (82.6%). Sulfonamide resistance was largely encoded by sul1 (63.6%) and sul2 (77.3%) genes with a high abundance of class 1 integrons (77.3%) of which 18.2% carried both Intl1 and Intl2. P. aeruginosa found in Sodwana Bay exhibits multi-drug resistance (MDRce) to several pharmaceutically important drugs with the potential to transfer antibiotic resistance to other bacteria if the judicious use of antibiotics for their treatment is not practiced.

Quantifying the distribution and site fidelity of a rare, non-commercial elasmobranch using local ecological knowledge

Fishery catch records offer limited data to assess the status of rare, non-commercial species, including some sharks. Despite marine megafauna creating an important source of revenue though tourism, basic spatial information required to create conservation strategies is not available for many of these species. A cost-effective approach to assess the distribution of rare, non-commercial species is required to manage resources and inform conservation strategies in data-deficient areas. This study provides new information on the distribution and abundance of the zebra shark in southern Africa and examines if local ecological knowledge can be used to identify spatial and temporal trends of rare, non-commercial elasmobranchs. Trends identified from fisher interviews at two locations were compared to those collected using structured dive surveys. Both fisher interviews and structured surveys identified similar hotspot areas and temporal changes in the zebra shark population. Photographs of zebra sharks taken by researchers, dive operators, and recreational scuba divers between Pomene and Sodwana Bay were used to identify and provide information on the size, sex and movement of individuals. A combination of geo-located data gathered from one hundred interviews conducted with fishers at four different locations within Mozambique and sightings information from scuba divers were used in a species distribution model to determine the relative importance of environmental predictors and identify further areas of suitable habitat. Sea surface temperature was the most important factor in the coldest months, with distance from shore most limiting habitat suitability at other times of year. This approach could be applied in data-deficient regions to highlight areas of interest, prioritise research activities and inform conservation actions for rare, non-commercial marine megafauna.

Upeneus floros, a new goatfish from South Africa and Mozambique, with updated taxonomic accounts for U. guttatus and U. pori and a key to Western Indian Ocean Upeneus species (Mullidae).

The highly diverse goatfish genus Upeneus (Mullidae) requires enhanced attention regarding the possible occurrence of undescribed species in insufficiently explored regions. This study focuses on the South-Western Indian Ocean region (SWIO), and on the so-called japonicus-group, a taxonomic species group of Upeneus. Based on in-situ observations and collections in Sodwana Bay, KwaZulu-Natal, South Africa, the Floros goatfish, U. floros n. sp., is described. Detailed comparative studies of colour patterns and morphological characters of all other 13 japonicus-group species were undertaken as well as COI barcoding. The new species occurs in the coastal area between Angoche, N Mozambique and KwaZulu-Natal and partly overlaps in distribution with two similar species, U. guttatus, widely distributed in the Indo-W Pacific, and U. saiab, assumed to be endemic in a small area off Angoche. Two additional japonicus-group species occurring in the SWIO, U. seychellensis from the Seychelles Bank and U. pori from the Mediterranean Sea (as Lessepsian migrant), Northern Red Sea and Madagascar, were also compared. Because specimens as well as in-situ photographs of U. floros have been erroneously identified as either U. guttatus or U. pori during previous studies, updated taxonomic accounts and diagnoses are provided for these species taking size-related and population differences into account. For U. pori, of which a single preserved specimen from SW Madagascar was known so far, a new record from NE Madagascar is reported based on three specimens and a fresh-colour photo. Upeneus floros can be distinguished from U. guttatus and U. pori by a combination of three characters: head length, first dorsal-fin height and number of gill rakers. Upeneus guttatus can be distinguished from the other two species by disproportionally higher anterior dorsal-fin spines vs. a proportional decrease of dorsal-fin spines in height, barbels mostly yellow vs. white or creamy-white, and slightly fewer pectoral-fin rays. COI barcoding detected a clear distinction between U. guttatus and U. floros and U. pori, respectively, but no significant divergence between the two latter species. COI barcoding also failed to differentiate several other Upeneus species which are clearly distinguished morphologically. Possible interrelationships between species distribution patterns and physical oceanography are discussed. An identification key for the 22 WIO Upeneus species is provided.

Hippocampus nalu, a new species of pygmy seahorse from South Africa, and the first record of a pygmy seahorse from the Indian Ocean (Teleostei, Syngnathidae).

A new species and the first confirmed record of a true pygmy seahorse from Africa, Hippocampus nalusp. nov., is herein described on the basis of two specimens, 18.9–22 mm SL, collected from flat sandy coral reef at 14–17 meters depth from Sodwana Bay, South Africa. The new taxon shares morphological synapomorphies with the previously described central Indo-Pacific pygmy seahorses, H. colemani, H. japapigu, H. pontohi, and H. satomiae, and H. waleananus, including diminutive size, twelve trunk rings, prominent cleithral ring and supracleithrum, spines on the fifth and twelfth superior and lateral trunk ridges, respectively, and prominent wing-like protrusions present on the first and/or second superior trunk rings posterior to the head. Hippocampus nalusp. nov. is primarily distinguished from its pygmy seahorse congeners by highly distinct spine morphology along the anterior segments of the superior trunk ridge. Comparative molecular analysis reveals that the new species demonstrates significant genetic divergence in the mitochondrial COI gene from the morphologically similar H. japapigu and H. pontohi (estimated uncorrected p-distances of 16.3% and 15.2%, respectively). Hippocampus nalusp. nov. represents the eighth member of the pygmy seahorse clade to be described from the Indo-Pacific, the first confirmed record from the African continent and the Indian Ocean, and an extension of more than 8000 km beyond the previously known range of pygmy seahorses from the Central and Western Indo-Pacific.

Ecosystem service values of sediment generation and entrapment by marginal coral reefs at Sodwana Bay, South Africa

Coral reefs provide a multitude of goods and services, some of which are difficult to value due to their intangible nature and the absence of markets to ascribe their relative worth. The coral reefs of Sodwana Bay on the northeast coast of South Africa provide several ecological goods and services, of which only two are considered here: namely, sediment generation and sediment entrapment. Both are deemed essential to the functioning of the Sodwana Bay economy. The replacement-cost method was used to estimate the annual financial cost of sediment provided to the study area if it were replaced by dredging. Sediment generation by the coral reefs was valued at R2.6–R4.8 million, and sediment entrapment valued at R71.8–R84.6 million, totalling between R74.4 million and R89.4 million (≈$5.6–$6.7 million, at R13.38/US$1) per year.

A new genus and species of fish parasitic cymothoid (Crustacea, Isopoda) from the Indian Ocean coast of South Africa, with a key to the externally attaching genera of Cymothoidae

Bambalocra intwalagen. et sp. nov. is described from Sodwana Bay, north-eastern South Africa. The monotypic genus is characterised by the broadly truncate anterior margin of the head with a ventral rostrum, coxae 2–5 being ventral in position not forming part of the body outline and not or barely visible in dorsal view, and the posterolateral margins of pereonites 6 and 7 are posteriorly produced and broadly rounded. The antennulae bases are widely separated, with both antennula and antenna slender. The species is known only from the type locality and the known hosts are species of Pomacanthidae (Angelfish). A revised key to the externally attaching genera of Cymothoidae is provided.

Three new species of acanthocephalans (Palaeacanthocephala) from marine fishes collected off the East Coast of South Africa

Three new species of acanthocephalans are described from marine fishes collected in Sodwana Bay, South Africa: Rhadinorhynchus gerberi n. sp. from Trachinotus botla (Shaw), Pararhadinorhynchus sodwanensis n. sp. from Pomadasys furcatus (Bloch et Schneider) and Transvena pichelinae n. sp. from Thalassoma purpureum (Forsskål). Transvena pichelinae n. sp. differs from the single existing species of the genus Transvena annulospinosa Pichelin et Cribb, 2001, by the lower number of longitudinal rows of hooks (10-12 vs 12-14, respectively) and fewer hooks in a row (5 vs 6-8), shorter blades of anterior hooks (55-63 vs 98), more posterior location of the ganglion (close to the posterior margin of the proboscis receptacle vs mid-level of the proboscis receptacle) and smaller eggs (50-58 × 13 µm vs 62-66 × 13-19 µm). Pararhadinorhynchus sodwanensis n. sp. differs from all known species of the genus by a combination of characters. It closely resembles unidentified species Pararhadinorhynchus sp. sensu Weaver and Smales (2014) in the presence of a similar number of longitudinal rows of hooks on the proboscis (16-18 vs 18) and hooks in a row (11-13 vs 13-14), but differs in the position of the lemnisci (extend to the level of the posterior end of the proboscis receptacle or slightly posterior vs extend to the mid-level of the receptacle), length of the proboscis receptacle (910-1180 µm vs 1,460 µm) and cement glands (870-880 µm vs 335-350 µm). Rhadinorhynchus gerberi n. sp. is distinguishable from all its congeners by a single field of 19-26 irregular circular rows of the tegumental spines on the anterior part of the trunk, 10 longitudinal rows of hooks on the proboscis with 29-32 hooks in each row, subterminal genital pore in both sexes, and distinct separation of the opening of the genital pore from the posterior edge of the trunk (240-480 μm) in females. Sequences for the 18S rDNA, 28S rDNA and cox1 genes were generated to molecularly characterise the species and assess their phylogenetic position. This study provides the first report based on molecular evidence for the presence of species of Transvena Pichelin et Cribb, 2001 and Pararhadinorhynchus Johnston et Edmonds, 1947 in African coastal fishes.

Metal concentrations in corals from South Africa and the Mascarene Basin: A first assessment for the Western Indian Ocean

Little knowledge exists on the state of metal contamination in corals from the Western Indian Ocean (WIO). Fragments of four soft and five hard coral genera were collected from five sites in the WIO– Sodwana Bay and Aliwal Shoal from South Africa, and Agalega, Rodrigues, and St. Brandon's Rock from the Mascarene Basin. Fragments were analysed for 31 metallic elements using inductively coupled plasma mass spectrometry. Corals from the WIO contained lower concentrations of most metals than corals from the Red Sea. South African corals contained higher concentrations of most of the metallic elements than the Mascarene corals. Sinularia was the coral with the most elements at the highest mean concentrations. A very high concentration of Ni was found in Sinularia (1300 mg/kg dm) from Sodwana Bay. Corals from the Mascarene Islands, especially Agalega, had comparatively low concentrations and could serve as a benchmark for corals from other regions.

Shallow-water Demospongiae (Porifera) from Sodwana Bay, iSimangaliso Wetland Park, South Africa.

33 species of shallow-water Demospongiae (Phylum Porifera) are described from Sodwana Bay, iSimangaliso Wetland Park, on the east coast of South Africa. Of the 33 species collected, 18 are redescribed from fresh material and 15 are new to science. Orders Clionaida, Poecilosclerida, Axinellida, Haplosclerida and Dictyoceratida are well represented in the collection with 4 to 6 species each, with the first three groups appearing to have the greatest diversity on the east coast of South Africa. The east coast of South Africa appears to have a high abundance of poecilosclerid and dictyoceratid sponges. The results of this study underscore the importance of poecilosclerid and dictyoceratid sponge fauna of the east coast of South Africa, in terms of the potential for the continued discovery of new species.

Assessment of the flocculating potentials of Alcaligenes faecalis Isolated from the Estuary of Sodwana Bay

Abstract Alcaligenes faecalis was previously isolated from Sodwana Bay, South Africa and was shown to be a bioflocculant producing microorganism. The bioflocculant production potential was further assessed through the optimization of the standardized culture media. The production of biofloculant as well as the flocculation was evaluated using different variables such as the size of inoculum, sources of carbon and nitrogen, time course and pH. Through optimization A. faecalis showed an improvement in the production of its bioflocculant and also flocculating activity for the following factors: flocculating activity of 71% for an inoculum size of 1%. The bioflocculant produced when maltose was used as source of carbon, showed flocculating activity of 91%, urea, as the most efficient nitrogen source, showed a flocculating activity of 97%, the optimum pH was 9. The time courses analysis between 60 and 72 hours showed the peak for flocculation and by implication highest level of bioflocculant production.

A Putative Inter-Generic Hybrid Between Conomurex Fischer and Gibberulus Jousseaume (Gastropoda: Strombidae) from South Africa

This paper highlights a putative inter-generic Conomurex x Gibberulus hybrid from the Sodwana Bay area, North Natal, Republic of South Africa. Putative hybridisation in the Strombidae is becoming ever more recognised at the intra-generic level. Much rarer are the inter- generic hybrids. The new putative hybrid indicates that inter-generic hybridisation may well be an evolutionary force in the radiation of Strombidae, facilitating both rapid reticulation and speciation.

Screening for Bioflocculant-Producing Bacteria from the Marine Environment of Sodwana Bay, South Africa

Abstract Flocculants are chemicals that mediate flocculation process, by aggregating colloids from suspension to form floc. Chemical flocculants are hazardous to the environment, which inform the search for safer and eco-friendly alternatives from microorganisms. Bacterial strains were isolated from water and sediment samples collected from Sodwana Bay, South Africa, and physiological properties of the bacterial strains were observed. Flocculation test using kaolin clay suspension was done on all isolates and the ones that showed flocculating activity were identified molecularly using 16 rRNA gene sequence analysis. Forty marine bacteria isolates were gotten from sediments and water samples collected from Sodwana Bay. Most of the isolates exhibited a range of colony pigmentation (pink, creamy, yellow, and white). After purification of individual isolates, they were screened for their potential to produce bioflocculant. The result revealed that isolates marked SOD3, SOD10, SOD12, SOD26, SOD27, SOD28, SOD32, SOD33 and SOD34 produced bioflocculants as shown by the flocculating activities from their crude extract. All these isolates showed good flocculation of kaolin clay suspension above 60% (flocculating activity) except SOD12. These bioflocculant producing isolates were identified as Pseudoalteromonas sp, Alcaligenes faecalis, Bacillus subtilis, Bacillus cereus, Bacillus stratosphericus. The results showed Sodwana Bay, South Africa as a reservoir of bacteria with potential to produce flocculants. However, further studies on the optimisation of culture conditions for bioflocculant production, extraction, characterisation and application of isolates is on the way to underscore the biotechnological importance of these microbes as producers of substitutes to harmful chemical flocculants commonly used in water and wastewater treatment.

Genetic diversity and population connectivity of the sea urchin Tripneustes gratilla along the South African coast

The collector sea urchin Tripneustes gratilla has been identified as a species with potential for aquaculture production in South Africa. The species’ roe is considered a culinary delicacy in Asia and Europe. However, T. gratilla remains genetically uncharacterised in South Africa. Therefore, the purpose of this study was to provide baseline genetic information consisting of estimates of genetic diversity and population stratification, which may aid in future sustainable use of this urchin resource. A total of 22 species-specific microsatellite markers were used for the genetic characterisation of T. gratilla samples from along the South African coast, at Haga Haga, Coffee Bay, Hibberdene, Ballito Bay and Sodwana Bay. A moderate level of genetic diversity was observed, with an average number of alleles of 7.89 and an average effective number of alleles of 6.57, as well as an average observed heterozygosity of 0.55. Population differentiation tests suggest that the geographically representative samples form part of a single, large interbreeding population, with a global Fst estimate of 0.02 (p > 0.05). This finding is likely explained by high levels of gene flow between these locations caused by extensive larval dispersal during the planktonic larval stage. The panmixia observed within these natural populations of T. gratilla indicate that they could be managed as a single genetic stock.

Intraspecific cleaning by juvenile Cape white seabream Diplodus capensis (Sparidae) off eastern South Africa

Juveniles of the Cape white seabream Diplodus capensis were observed cleaning adult conspecifics in a large tidepool off Sodwana Bay, South Africa. Although nine other tropical fish species were present and interacted with a nearby pair of Labroides cleaner wrasses, only adults of D. capensis posed for and were cleaned by the D. capensis juveniles. Such cleaning interactions have not been reported previously for this species or among marine fishes off South Africa, and thus add to the growing list of facultative cleaners globally.